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Soil and groundwater investigations have previously been performed at each area. The project <br /> RI Report was issued on 24 August 2000 and the FS on 21 September 2000. In response to <br />�I DTSC comments, <br /> an amended FS was submitted on 15 November 2000, and a final addendum to <br /> the FS on 25 May 2001. The amended FS selected remedial action objectives (RAOs)which <br /> included 11 Contaminants of Concern(CDCs) in soil, and defaulted to drinking water standards <br /> as the RAOs for groundwater. <br /> i <br /> ES 1.0 Operable Units <br /> The Site consists of six parcels, referred to as areas, which have been grouped into two Operable <br /> I Units (OUs). Operable Unit 1 (OU I) consists of Area 10, Area 11, and Area 20, and Operable <br /> Unit 2 (OU2) consists of Area 15, Area 16, and Area 21. OUl is comprised of parcels having <br /> only soil contamination, whereas OU2 contains parcels with both groundwater and soil <br /> contamination. The groundwater contamination in OU2 is associated with releases of petroleum <br /> hydrocarbons from former underground storage tanks (USTs). Analytical results for <br /> r <br /> groundwater,samples collected during previous site investigations at OUl did not detect elevated <br /> concentrations of constituents that would require cleanup. <br /> Structures that previously existed at OU I were demolished prior to beginning the RI work in <br /> 1999,but some below grade improvements remained in place. Single-story metal, wood frame, <br /> and brick structures were present at OU2 until December 2004. From December 2003 through <br /> March 2004, all structures and subsurface improvements were removed from the Site. <br /> f <br /> ES 2.0 Remedial Selection and Planning <br /> E Ten soil remediation technologies were initially screened, including three capping alternatives, <br /> i <br /> five treatment technologies, onsite excavation and capping, and the no-action alternative for <br /> F <br /> OUsl and 2. Nine groundwater treatment technologies, including two containment barriers, four <br /> treatment approaches, pump-and-treat, monitoring-only, and the no-action alternative were <br /> evaluated for OU2. <br /> 25971025.DGD 2 11 August 2005 <br /> i <br />